Paint.



' WAUGH, a citizen of the United States, residtoan arid climate is made in contradistinc- To all it may concern:

UNITED srarns PATENT one MERRIWEATHERJ. WAUGH, or LINCOLN, NEBRASKA.

Be it known that I, MERRIwEA'rrmR J.

ing at Lincoln, Lancaster county, Nebraska, have invented certain new and useful Improvements in" Paints, of which the follow produce a controllable paint coat of hetero-' geneous-chemical and physical structure to withstand the usual temperature changes of an arid climate, the paint having a maximum of elasticity and adhesive power, correspondin with that of the expansion and contraction of the painted surface to which it is applied, thus rendering the same climate proof. It is to be understood that reference tion to normal, humid and dry climates, where the peculiar weather conditions affect paints differently. In arid climates the chief destructive agencies are sunlight and excessive heat, together with frequent abrupt temperature changes which cause serious movements of the painted surface by contraction and expansion.

'In the practice of this invention I have found. it desirable to'employ a coarse pigment of chemically stable character and crystalline structure to furnish points for capillary action for ivinga coat of sufiicient thickness. To fill the spaces between these coarse particles, pigments of great fineness are added, both for the purpose of shielding the easily destroyed linoxyn (dried linseed oil) from atmospheric action and to render this oil coat impermeable by gases and moisture, as well as tof give a hiding power or opacity to the paint. I' have found it desirable to use approximately 75% sublimed white lead as the major pigment,-

since it is not only an exceedingly fine grained material. (diameter of particle 1/35000 inch) but, in addition, it is of great chemical stability. For generalexterior use it is'necessary to employ a hardening agent in the coat, because the coat made-with sublimed white lead or other lead pigment alone is physically too soft to withstand abrasion,- and it is for this purpose that approximately 10% zinc oxid is preferably employed. Zinc oxid, when mixed with linseed oil and the proper amount of drier, sets and dries more" PAINT.

Specification of Letters Patent. Patented Mar. 21, 1911- Application filed June 27,1910. Serial No. 568,989.

slowly than white lead Nevertheless, this drying continues in the form of progressive exldation until the surface becomes very hard. A comparsion between zinc oxid and white lead paints shows that the progressive oxidation which takes place .when white lead dries produces a chalky mixture, while the reverse is true of zinc oxid, which pro duces a hard, vitreous surface. Owing, therefore, ,to the diverse effects of the two pigments, a combination of sublimed white lead and zinc is for practical purposes desirable.

Approximately 10% fibrous magnesium silicate is employed as an inert pigment, since this material has the added-physical advantage of presenting what is known as a tooth, which is especially desirable for repainting, and it is inert asan extender or filler in paint and does not combine with any" other pigment or vehicle. Fibrous magnesium silicate preferably in the form of comparatively long hairlike crystals of asbestos is desirable, since it tendsto remain in suspension and to retain the admixed pigments I ments is added a fourth material (approximately 5%), which preferably is a matter of selection, the essential being that it shall be crystalline in character, with rather obtuse angles, it having beenshown that materials of acute angular fracture, exert too much of a retardlng or holding influence on the brush, thus making the labor of ap plication excessive. A blend .of fine pigments with pigments of moderately angular =crystallinity is the only mix so, far found which brushes uniformly, and it is to secure a proper modification of this brushing character that the fourth pigment is added there-.

to. Among the available materials may be cited: calcite (calcium. carbonate), talc (a tabular magnesium silicate), china' clay or kaolin (hydrated aluminumfsilicate), ba-

rytes (native barium sulfate), aragonite-and other forms'ofcalciumcarbonate, plaster-j 'of-paris (anhydrous calcium sulfatef), dolo- -'mite and other mixed carbonates, eldsp'ar and other complex silicates.

An analysis discloses that one or more pigments ofcoarse grain are employed to give a requisite thickness of coat; that two pigments of extreme and uniform fineness and grain are employed to give opacity and impermeability as Well as elasticity and durability; that an added crystalline material is utilized to modify brushing; that a selection of materials is made to avoid destructive reaction by the pigments upon the paint vehicle; and that the same is a mix of non poisonous character.

Without specifically limiting myself to the foregoing, I claim:

1. In combination With asuitable paint vehicle, a, major pigment composed of approximately 75% sublimedwhite lead, approximately 10% time oxi d', approximately 10% fibrous magnesium silicate, and a fourth proximately 10% zinc oxid, approximately 10 fibrous magnesium silicate and approxi- 'mately 5% of crystallized calcium carbonate of rather obtuse angular formation for facilitating in application of the paint.

MERRHVEATHER J. WAUGH.

\Vitnesses I R. A. WVARREN, RAY C. HALL. 

